Image Processing Hardware Design--Application In Railroad Track Flaw On-line Detection

Railroad track flaw on-line detection is a very important measure to ensure the safety of railway transportation. We developed a railroad track flaw on-line detection system based on video image for Jilin Railway Research Institute. The system gets the high quality track image using the high-speed line scan CCD, accomplishs the image processing in real-time using DSP(Digital Signal Processor), achieves the track flaw detection using edge detection algorithm. The papar introduces the hardware design, the software development, the testing of the system and the examination results, including the design of Channel Link standard receiving circuitry of the line scan CCD, the degign of DSP Image Processing System, the design of CCD Display System and the development of software based on TMS320VC33. The system has the following features:1. Image acquisition technology based on high-resolution line scan CCD and Channel Link standard. The line scan CCD only captures a line of the surface of the railroad track. Its width is less than 1mm. Two-dimensional images are acquired by successive single-line scans while the track moves (perpendicularly) past the line of pixels in the image sensors. The advantages of line scan cameras include smear-free images of fast-moving objects eliminating the need for cumbersome strobe illumination, and continuous imaging of the track without overlapping.2. High-speed Image Processing System based on TMS320VC33 .The system should accomplish the complicated processing of a frame of image of 1024*512 pixels in 25ms, including such algorithm as noise removing, edge orientation, flaw detection and identification. To achieve such high-speed processing in real-time, a multi-DSP parallel processing stream overlap technology is employed to meet the need of high speed.3. In the system, we used programmable logic devices, which improve capability of the circuitry, and reduce size of the PCB board.